Generally, a display device displays a two-dimensional image (hereinafter, referred to as “2D image”). Recently, according to increased demands for a three-dimensional image (hereinafter, referred to as “3D image”) in the field of a game or movie, a display device displaying 3D images is being developed. A 3D image is recognized by inputting a pair of 2D images to both eyes of an observer, and fusing the input images in the brain of the observer.
A 3D image display device (hereinafter, referred to as “3D device”) may be classified into a stereo-scopic device and an auto stereo-scopic device. In the auto stereo-scopic device, a parallex barrier-type device disclosed in Patent Document 1 or a lenticular lens-type device disclosed in Patent Document 2 is generally used.